a. Field of the Invention
This invention relates to a new process for preparing certain pregn-20-yne compounds and to a novel steroid produced thereby.
B. Description of the Prior Art
Clinton and Manson U.S. Pat. No. 3,135,743 discloses a series of steroido[2,3-d]isoxazoles, useful as endocrinological agents, including compounds of the formulas: ##STR1## where R is H or CH.sub.3. The compounds of formulas I and II were prepared by formation of the isoxazole ring from the corresponding 3-oxo steroids, 17.alpha.-(C.tbd.CR)-17.beta.-hydroxyandrostan-3-one or 17.alpha.-(C.tbd.CR)-17.beta.-hydroxyandrost-4-en-3-one. The 3-oxo steroid was caused to react with ethyl formate in the presence of a base to form the 2-hydroxymethylene derivative. The latter was then interacted with hydroxylamine to form the steroido[2,3-d]isoxazole nucleus.
Clinton and Manson U.S. Pat. Nos. 3,135,743 and 3,296,255 teach that steroido[2,3-d]isoxazoles are cleaved sith strong bases to form 2-cyano-3-oxo steroids.
The formation of 17.alpha.-ethynyl-17.beta.-hydroxy steroids by reaction of 17-oxo steroids with ethynyl Grignard reagents or alkali metal acetylides is known, e.g., Pierdet U.S. Pat. No. 3,790,564, but the reaction has never been applied to 17-oxo steroids containing an isoxazole moiety.